Mark my words: the tower will be closed with the release of rise of iron.
So no decrypting engrams en opening faction packages. Bungie started this infection event only to close the tower and guardians are not able to level up as fast like with the taken king.
UPDATE
deej stated that it will not be closed at launch
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It won't be closed https://twitter.com/deej_bng/status/777244705100664832